Less than carload shipper



March 17, 1936.

r R. v. GRAYSON LESS THAN CARLOAD SHIPPER 3 SheetsSheet 1 Filed April 9,1934 R LPH V, RAYSON March 17, 1936.

R. v. GRAYSON 2,034,139 LESS THAN CARLOAD SHIPPER Filed April 9, 1934 3Sheets-sheaf. 2

BIB

March -17, 1936. R. v. GRAYSON LESS THAN CARLOAD SHIPPER Filed April 9,1934 3 Sheets-Sheet 3 HN HHHHHU .irill RALPH GRAyso/v Patented Mar. 17,1936 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to portable self-contained refrigerator unitsadapted to be employed in plurality in railroad or steamshiptransportation in the shipment of less than carload lots of 5 productsdesigned for different delivery points or which require to be maintainedat different refrigerating temperatures enroute The invention has forits principal object the provision of refrigerating shipping units asde- 19 scribed, adapted to be removed from the car or hold of the vesseland set upon the dock or station platform without interrupting therefrigerating function of said units.

Another object of the invention is the provision of a portable less thancarload shipping unit which when used in plurality so as to occupy theentire cargo space in the hold of the vessel or upon the car permitsloading 100% of the lading space by virtue of the individual re- 20frigerating system included in each unit. This cannot be done in thestandard ice refrigerated car or hold on account of the necessity forproviding ample space for circulation of air about the cargo parcels inorder to obtain the necessary 25 refrigerating temperature in all partsof the lading space.

Still another object of the invention is the provision of a portableself-refrigerating less than carload shipping unit that requires no bat-30 teries or electrical instrumentalities, no steam or vidual to saidunit and removable without thenecessity of disturbing the refrigeratedproduct, i

40 and means operable responsive to the pressure of gaseous refrigerantin said tank forcreating a positive circulation throughout therefrigerated chamber.

Another object of the invention is the pro- 45 vision of an evaporatortank in association with the refrigerated chamber as above described inwhich conservation refrigerant is obtained by the provision of inner andouter annular spaces surrounding said tank, the outermost of which ismaintained in vacuo while the inner annular space is controlledaccording to the refrigerating demands within the refrigerated chamber,the

air in said inner annular space being normally inert and functioning asan insulating medium,

55 but circulating through the inner annular space and through therefrigerated chamber when the temperature of the latter has risen to apredetermined value.

Still another object of the invention is the provision of a motor foroperating the means by which the air is circulated through said chamberonly when the pressure of the gaseous refrigerant within the evaporatortank has attained predetermined pressure value.

Other objects of the invention will appear as the following descriptionof a preferred and practical embodiment thereof proceeds.

In the drawings throughout the several figures of which the samecharacters of reference have been employed to designate identical parts:

Figure 1 is a plan viewof the less than carload shipping unit partlyshown in section;

Figure 2 is a cross section;

Figure 3 is a cross section taken at right angles to the section shownin Figure 2;

Figure 4 is a front elevation;

Figure 5 is a cross section through the removable evaporator tank takenalong the line 5-5 of Figure 11;

Figure 6 is a longitudinal view of thermostatic means for controllingthe dampers associated with the evaporator tank, part being shown insection;

Figure '7 is 'a longitudinal section through the fluid pressure motorwhich actuates the dampers;

Figure 8 is a section through the control valve which supplies fluidpressure to the motor;

Figure 9 is the fragmentary view showing the seating face of the valve;

Figure 10 is a positive view of the valve; and

Figure 11 is a longitudinal section through the evaporator tank.

Referring now in detail to the several figures the numeral l representsin general the less than carload shipper which comprises an outer casing2 formed by corrugated side and end walls 3 and 4, respectively, and topand bottom walls 5 and 6, respectively. Within the casing 2 is anenclosure I of smaller dimensions arranged so as to leave a of the outercasing, best shown in Figure 1, and

by providing projecting plates I I from the top corner portions of theenclosure 1, the plates ll= resting upon the angle brackets and beingwelded at their points of contact I 2. The metallic leakage 8 betweenthe enclosure 1 and the casing 2 is limited to the extremely small arearepresented by the point of weld 12. At all other'points, exceptingwhere provision is made for the reception of the evaporator tank, theenclosure 1 is spaced from the casing 2 by a layer of insulation. Sincethe enclosure is suspended from the casing at a plurality of pointslying in the same plane it is obvious that relative elongation of thecasing to the enclosure will not have any disruptive effect upon thepoints of weld nor will it impart strains to the well structure eitherof the enclosure or casing.

The shipper l is preferably supported by casters l3, one under eachcorner of the bottom, one pair of these being preferably rotatable in afixed axial direction while the other pair swivel u'pon vertical axes.At their upper corners the shippers are preferably provided with rings14. The shippers are designed to be arranged side by side upon a fiatcar or suitably positioned in the hold of a vessel. They are lifted whenthe delivery point is reached by a suitable mechanical hoist havinghooks co-operating with the rings l4 and by means of which the shippersare placed upon a station platform or dock. -The casters afiord meansfor pushing them around in any desired direction upon the platform andalso provide space beneath said shippers for the insertion of theforward end of a hand truck by means of which the individual shippingunits can be transported from place to place.

The top walls 5 of the shipping units I slope from a central ridge l5,constituting a roof for shedding rain. In the middle of the roof andextending from back to front of the shipper is an arcuate valley l6 andin the middle is a hatchway I1 leading into the chamber within theenclosure 1. The concave valley acts as a slideway for receiving theevaporator tank I8 and the hatchway l1 affords an o ening into therefrigerated chamber which is c osed by the evaporator tank when thelatter is in place. The evaporator tank has certain protuberances l9 and28 which will presently be explained and these are accommodated throughthe opening in the hatchway. A framelike felt pad 2| borders thehatchway ,I1, and upon this pad the evaporator tank rests forming asubstantially fluid-tight seal with the wall of the refrigeratedchamber. The evaporator tank 18 is held in place by flexible metalstraps 22 secured at one end to the top wall of the casing as indicatedat 23 in Figure 3 and connected by means of a turn buckle 24 to a lug 25fixed to the top wall of the casing at the opposite side. The strap maybe tightened against the evaporator tank by manipulating the turn buckle24.

The evaporator tank comprises a container 26 preferably cylindricalpermanently closed at one end and at the other having a removable header21 through which the container may be charged with blocks of dry ice.The container 26 is surrounded by a shell 28 of larger diameter thansaid container constituting a jacket for the inner air space whichimmediately surrounds the container 25. Said jacket is in turnsurrounded by a spaced shell 29. The inner air space communicates atupper and lower points with the refrigerated chamber by means of theinlet and outlet ports outlet ports so as to form a chamber from whichthe air may be suitably evacuated through a check valve 38.

The inlet and outlet ports are controlled by dampers 3| and 32interconnected in a manner presently to be described andthermostatically controlled responsive to the temperature of therefrigerated chamber so as to remain closed, rendering the air withinthe shell 28 inert and adding to the thermal isolationof the container26, when the refrigerating demands of the refrigerated chamber aresmall, but opening so as to provide a convectional fiow of the air ofsaid refrigerated chamber through the air space within the shell 28 whenthe demands of the refrigerated chamber exceed the determined value atwhich the thermostatic control operates. A bafile 48 is arranged in theair space within the shell 28 and between the inlet and outlet ports l9and 28 so as to determine a unidirectional flow of air through said airspace. The baflie is secured as by welding against one wall of said airspace, but slightly spaced from the other as at 49 to defeat thecontinuity of a thermal leakage passage from the container 26 to theshell 28.

Thermal isolation of said container from said shell is further enhancedthrough the nature of 1 26 or shell 28 and bearing with their apicaledges against the other of said members. Heat leakage is thus confinedto the very small area of contact between said apical edges and the wallwhich they engage.

Between the shells 28 and 29 and in the evacuated chamber are smallcylindrical spacers 5| welded to one of said shells and making linecontact with the other.

Normally, when the dampers are closed very little sublimation of thesolid refrigerant within the container 26 takes place and but littlepressure is generated in the evaporator tank. On the other hand, whenthe dampers are open and the relatively warm air from the refrigeratedchamber is circulating upward through the inlet 19 and outward throughthe outlet 28, the solid refrigerant is sublimed at a relatively rapidrate and considerable pressure is stored in the evaporator tank.. Thispressure is made use of when a pre determined pressure value has beenexceeded in circulating air through the refrigerated chamber by means ofa turbo-blower unit 33 comprising a turbine 34 and the blower 35 drivenby said turbine. The blower is supplied with gaseous refrigerant underpressure by a conduit 36 communicating with the evaporator tank. Theturbine exhausts through a conduit 31 which discharges intotheinsulating space between the top of the enclosure 1 and the casing 2.The conduit 31 is preferably formed with convolutions 38 so as to salveto the refrigerated chamber the waste refrigerating capacity remainingin the exhaust gas from the turbine 34. Since the carbon dioxide gas isheavier than air, it percolates the fibrous insulating material in thespace between the enclosure 1 and easing 2, descends to the bottom ofsaid space and fills said space to the top, finally exhausting toatmosphere through a suitable aperture 39.

Since the rate of evaporation of the refrigerant in the evaporator tankis in general at too slow a rate to continuously generate sufiicientpressure to operate the blower 34, an automatic pressure valve All isintercalated in the conduit 36, controlling said conduit so as to keepit closed until a predetermined pressure value has been built up withinthe evaporator. tank and then opening it to transmit said pressure tothe blower. Thus the operation of the blower is intermittent.

The blower has an inlet 4! taking air from the top of the refrigeratedchamber and an outlet d2 which extends down to one of the bottom edgesof the enclosure 1 at which point it debouches into a pipe 83 extendingpreferably substantially the full length of said edges. The bottom wallof the enclosure 1 has corrugations M defining between them airways,beneath the goods stored in said shipping units and which goods restupon the peaks of said corrugations. The pipe 43 is provided with aplurality of laterals 45 extending through the spaces between saidcorrugations and beneath the goods and said laterals are perforated asat 4B and til permitting the air from said blower to be dischargedbeneath the shipment and at numerous points quite uniformly distributedon the underside of said shipment.

The thermostatic means for operating the dampers 3i and 32 comprise abulb 52 adapted to be suitably arranged in the refrigerated chamber forcontaining a volatile fluid, said bulb communicating with a sylphon 53,the expansive or contractive movements of which .scillate a valve 54controlling the admission of gaseous refrigerant under pressure to thepiston chamber 55 of a fluid ressure motor 58. Said motor has a piston'1 actuated by the fluid pressure within the chamber 55 andreciprocating a link 58 connected to hinged levers 59 to which saiddampers are secured.

The adjustment of the thermostatic control may be effected by a dial tilforming a turn buckle at the ends of threaded sections of the rod whichconnected the sylphon to the valve whereby the time of opening saidvalve may be changed.

The valve is preferably of the oscillating type sliding upon its seat.It is shown in Figure as having a frustc-conical seating surface 8iwhich slides as indicated in Figure 8 upon a frusto-conical seat havinga port 62 communicating with the pressure chamber of the motor, and avent port.

83. The valve has a through-port 65 opening at one end in the seatingsurface and adapted to register with the port 82. The other end of thethrough-ports opens into a chamber 65 which communicates by means of atube 66 with the conduit 3B. This is the open position of the valve. Theseating surface also has an arcuate channel 61 which in another positionof the valve bridges the ports 62 and 63 discharging the pressure withinthe piston chamber 55 and permitting the return of the piston 51 underthe urge of the spring 68. Upon this return movement of the piston thedampers 3| and 32 close.

The shipping unit is filled through a refrigerator door 59 of usualconstruction.

When the evaporator tank has become exhausted, it may be charged byremoving the head and filling it with chunks of dry ice. It is notnecessary each time it is charged to remove the evaporator tank from theunit. Occasionally, however, the evaporator tank will requirereplacement through need of repair and for other causes. It can bereadily removed merely by loosening the turnbuckles 34, and unlatchingthe straps 22 upon making two pipe disconnections within the unit I,namely uncoupling the pipe 36 which conducts gaseous refrigerant to theblower and disconnecting the tube 66 which supplies pressure to thethermal motor, the evaporator tank is free for removal and replacement.

While I have in the above disclosure described what I believe to be apreferred and practical embodiment of my invention, it is to beunderstood that the details of construction as shown and described aremerely by Way of example and not to be construed as limiting the scopeof the invention as claimed.

What I claim is:

1. Self-refrigerating shipping unit comprising an outer casing and aninner enclosure having an insulating space therebetween, said innerenclosure defining a refrigerated chamber, means for refrigerating saidchamber, and means suspending said enclosure solely at spaced pointsadjacent the top of said enclosure and casing to permit thermalelongation of said enclosure independently of said casing, said pointsof suspension having the minimum cross section commensurate withnecessary supporting strength, so as to minimize heat leakage from saidenclosure to said casing.

2. Self-refrigerating shipping unit as claimed in claim 1, thesuspending means comprising angle brackets subtending the corners ofsaid casingand plates extending from the corners of said enclosureresting upon said angle supports and secured thereto.

3. Self-refrigerating shipping unit comprising an outer corrugatedcasing and an inner enclo- .sure, having an insulating spacetherebetween,

said inner enclosure being suspended from the outer casing adjacent thetop, porous insulating material filling said insulating space, saidenclosure defining a refrigerated chamber, means with in said chamberfor circulating air therethrough, a fluid pressure motor for operatingsaid air circu lating means, a detachable evaporator associated withsaid refrigerated chamber adapted to contain a sublimating refrigerantand to retain the gas evolving from said refrigerant under pressure, aconduit establishing communication between said evaporator and saidmotor for supplying gaseous refrigerant under pressure to said motor,and a valve in said conduit controlling the passage of gaseousrefrigerant therethrough opening only upon a predetermined pressurevalue of said refrigerant.

4. Self-refrigerating shipping unit as claimed in claim 3, the exhaustfrom said motor discharging into said insulating space. i

5. Self-refrigerating shipping unit as claimed in claim 3, the bottomWall of said enclosure having elevations for supporting the refrigeratedproduct thereupon and defining fiues therebetween, said air circulatingmeans including branch pipes discharging within said flues.

6. Self-refrigerating shipping unit comprising an outer casing and aninner enclosure having an insulating space therebetween, the top of saidshipping unit being formed with a hatch extending through the top wallsof said casing and enclosure, an evaporating tank for sublimatingrefrigerant adapted to seat upon said hatch, a turbo-blower unit withinthe chamber defined by said enclosure, the blower element of said unitbeing arranged to circulate air from the top of said chamber to thelower part thereof, the turbine element of said unit being adapted tohave its inlet connected to said evaporator tank and its outlet to thespace between said' casing and enclosure, said turbine being operated bygaseous refrigerant under pressure from said evaporating tank, means forinhibiting the passage of gaseous refrigerant from said evaporating tankto said turbine until a determined pressure value has been built up insaid evaporating tank, means forming a jacket surrounding saidevaporator tank having inlet and outlet ports at different levels, saidports extending through said hatch and communicating with therefrigerated chamber, dampers mounted on said evaporator tank forcontrolling said inlet and outlet ports, and thermo-motive means carriedby said evaporator tank and responsive to the temperature of saidrefrigerated chamber for controlling said dampers arranged to open themwhen the refrigerating demands are relatively great and close them whensaid demands are relatively small.

7. Self-refrigerating shipping unit as claimed in claim 6, saidevaporator tank including an outer shell enclosing a surrounding spacein which an insulating vacuum is maintained.

8. Self-refrigerating shipping unit comprising an outer casing and aninner enclosure having an insulating space therebetween, the top of saidshipping unit being formed with a concave channel providing a slide-Wayfor a correspondingly shaped evaporator tank, a hatch extending throughthe bottom wall of said slide-way forming an opening into therefrigerated chamber within said enclosure, an evaporating tank for asublimating refrigerant adapted to seat ,upon said hatch andsubstantially seal the same, a turbo-blower unit within saidrefrigerated chamber, the blower element of which being arranged tocirculate air from the top of said chamber to the lower part thereof,the turbine element of said unit being adapted to have its inletconnected to said evaporator tank and its outlet space between saidcasing and enclosure, said turbine being operated by gaseous refrigerantunder pressure, derived from said evaporating tank, and means forinhibiting the supply of gaseous refrigerant from said turbine to saidevaporator tank until a determined pressure value has been built up insaid evaporator tank.

9. Self-refrigerating shipping unit as claimed in claim 8, saidevaporator comprising a container and concentric spaced shellssurrounding said container, the inner shell forming with said containeran air space, the outer shell forming with the inner shell an evacuatedspace, inlet and outlet ports at diiferent levels communicating withsaid air space, dampers carried by said tank controlling said inlet andoutlet ports, and thermo-motive means also carried by said evaporatortank and responsive to temperature changes within the refrigeratedchamber for operating said dampers when the -refrigerating demands arelarge and closing them when the refrigerating demands are relativelysmall.

10. Self-refrigerating shipping unit as claimed in claim 8, saidevaporator comprising a container and concentric spaced shellssurrounding said container, the inner shell forming with said containeran air space, the outer shell forming with the inner shell an evacuatedspace, inlet and outlet ports at difierent levels communicating withsaid air space, dampers carried by said tank controlling said inlet andoutlet ports, and thermo-motive means also carried by said evaporatortank and responsive to temperature changes .within the refrigeratedchamber for operating said dampers when the refrigerating demands arelarge and closing them when the refrigerating demands are relativelysmall, in-

eluding spacers of triangular cross section between said container andinner shell making edge engagement with the latter, and cylindricalspacers between said shells making line contact therewith.

RALPH V. GRAYSON.

